Thursday, May 28, 2015

Yes! Tree Swallows have claimed the second nest box! After the original Tree Swallow nest in Box #1 was hijacked by Bluebirds on May 10th, we finally mounted a second box (Box #2) on May 19th.

A pair of Tree Swallows claimed Box #2 on May 23rd and have now started building a nest inside of it. The photo to the right shows the female Tree Swallow peeking out of Box #2 and
holding straw in her bill, straw that she would be adding to the nest inside the box The male is to the left, flying away from
the box.

Sadly, however, this pair of Tree Swallows does not appear to be the same pair of Tree Swallows who were chased out of Box #1 by the Bluebirds on May 10th.

I felt so sorry for the female Tree Swallow who had been building a nest in Box #1 for 9 full days when she and her mate were chased away by the Bluebirds. The female Tree Swallow and her mate kept hanging around my yard for several days thereafter, mating on the fence during the mornings. I knew that the female was ready to lay eggs and hoped and prayed that she would find a place to lay them.

Back to Box #1: The Bluebirds seem to be doing fine, and the female has laid five eggs! The female is often inside the box incubating the eggs, but she sometimes takes breaks and leaves the box, especially during warm afternoons.

While the female is inside the box, the male brings her food and feeds her through the box's hole, just as if he is feeding a baby. This is an excellent way for him to practice what he will have to do once the eggs hatch!

A couple of mornings ago, I observed the female Bluebird peeking out of the hole of the nest box. Soon the male came to the box and fed her through the hole. To my surprise, when the male flew from the box, the female left the box and flew after him! I wonder if she was chastising him for not feeding her often enough.

The size of the hole on a Bluebird nest box easily accommodates Tree Swallows as well as Bluebirds. In geographical regions where both species breed, the two species commonly compete for nest sites.

It is often recommended to mount nest boxes in pairs, one for Bluebirds and one for Tree Swallows. The reason for this is that Bluebirds and Tree Swallows can coexist in the same breeding territory as long as they both have boxes in which to nest. Also, the Tree Swallows can help defend both boxes from predators by swooping at any bird, animal, or even a human, that comes close to the boxes.

A pair of Bluebirds requires a radius of 300 feet for its territory and will chase away any other Bluebirds within that radius. However, Bluebirds that are already established in a nest will not chase nearby nesting Tree Swallows away.

Tree Swallows defend a territory from other Tree Swallows, but only within a 100-foot radius. They will tolerate Bluebirds in their territory because the diets of Tree Swallows and Bluebirds differ immensely.

While Bluebirds feed on insects and larvae on the ground, Tree Swallows feed on flying insects. Thus, there is no competition for food within the same territory.

The photo on the right shows the male Bluebird, who has just captured some food.

The recommendation is to mount the two boxes, one for Bluebirds and the other for Tree Swallows, no more than five to ten feet apart. We tried to do that, but were unsuccessful.

We were restrained by the parameters specified by Bluebird organizations and also by restrictions from our landlord. Bluebird specifications dictate that, in order to help guard against predators (and we have plenty of roaming cats around here), a Bluebird box must be mounted on a pole and in an open area, preferably at least 20 feet from a building, fence, or tree. Our landlord restricted us from being able to mount the boxes in the middle of the lawn. The reason for the restriction was that this type of location would add complications to the chore of lawn mowing.

We received permission from our landlord to mount a box near the septic tank opening, which is about 25 feet from our building. So that is where we mounted Box #1 on April 24th.

It took only a week for birds to claim Box #1, but the birds ended up being Tree Swallows rather than Bluebirds. After Bluebirds hijacked the box from the Tree Swallows only nine days later, we decided that we needed to mount a second nest box, one for the Tree Swallows. The photo to the left shows the two Bluebirds on Box #1 the day they hijacked the box. The female Bluebird is peering through the hole to check the inside of the box. The male on the roof looks like he is jumping for joy at having procured a suitable nest box!

We tried to mount Box #2 about 5 feet from Box #1 where it would have not interfered with lawn mowing. However, a layer of rock about 6 inches below the surface of the ground prevented the driving of the pole far enough into the soil.

The only option at that point was to mount Box #2 along the horse pasture fence where our landlord had also given us permission. To mount a nest box along a fence is not an optimal choice because predators can sometimes use a fence to gain access to a nest. However, this is the only choice our landlord gave us based on avoidance of lawn-mowing complications.

We ended up locating Box #2 between two metal fence poles that are about 4.3 feet high and 8 feet apart. The box is located 28 feet from a 11-foot high wooden fence post that serves as a lookout tower for several different species of birds. We are hoping that the fence post is far enough away from Box #2 that a large bird cannot use the post to prey upon the birds using the box.

The photo below, from the morning of May 28th, shows Box #2 on the left, separated from the high fence post by three metal fence poles.

The photo below, from May 20th, the day after we mounted Box #2, shows Box #1 in the foreground on the right, with Box #2 in the background. The two boxes are about 75 feet apart although in the photo they look closer. This photo was taken three days before the Tree Swallows arrived and claimed Box #2. I cannot identify the bird perching on top of Box #2 in the photo, but the Bluebirds from Box #1 are perching on the fence. The male Bluebird is on the wire at the center of the photo, and the female is on top of the fence pole on the right.

While Box #1 is about 4.3 feet high, we mounted Box #2 a little higher. The distance from the ground to the lower edge of Box #2 is about 5.3 feet.

The higher a nest box is from the ground, the lesser the chance that House Sparrows will use the box. This is a matter of great concern because we do have House Sparrows in close proximity, and House Sparrows have been known to enter a nest box and destroy the young of the host species.

The day after we mounted Box #2, I noticed a House Sparrow hovering near the entrance hole of that box and perching on the fence next to the box. To my delight, the male Bluebird from Box #1 immediately flew to Box #2 and chased the House Sparrow away!

Also to my delight, when the Tree Swallows arrived and began investigating Box #2 on May 23rd, the Bluebirds did not chase them away! What I had read about Bluebirds and Tree Swallows peacefully nesting near one another had proven true. To this day, the Tree Swallows are still guarding Box #2, and the Bluebirds have not bothered the Tree Swallows.

The photo below shows Box #2 on the morning of May 24th, just one day after the new pair of Tree Swallows claimed the box. The male Tree Swallow is perching on the fence pole, while the female is inside the box, peeking out.

Optimally, we should have already had Box #1 mounted by early March when our local Bluebirds start choosing their mates and searching for nest sites. But we did not get it mounted until April 24th. For one thing, my neighbor was mounting these boxes for me as favor. For another, it took a great deal of time for us to decide upon a nest box design, plan its location, and gather the parts needed for mounting. Besides, in early March it was likely that the ground would have been too frozen for driving a pole into the ground.

In early March, no Tree Swallows would have been on the scene. That is because, while Bluebirds remain in this area all winter long, Tree Swallows are migratory and do not arrive here until early April. Although Bluebirds tend to be feisty and defensive of their chosen nesting sites, they would not have had any competition from Tree Swallows during March.

If you don't want to miss the news about the hatching of the Bluebird eggs or whether the female Tree Swallow lays eggs in Box #2, you can follow this blog by entering your email address at the top right of this page.

During this past March (2015), I did not observe as many
Bluebirds around here as I had during March 2014.Why?There could be several reasons.

Bluebird, Nov. 9, 2014

For one, we had unseasonably wintry weather here during November
2014.It was extraordinarily cold, and
we had two snowfalls that month – quite unusual for this area.

During the winter of 2013 to 2014, each month I would observe at least one Bluebird around my yard. But this past winter was different. The Bluebird shown on the left that I saw on November 9, 2014, would be the last Bluebird I would see until March 9, 2015. On March 9th I sighted a pair of Bluebirds, one at a time, on the wire across the road from where I live. I did not see any Bluebirds near my yard until March 23rd.

Although our local Bluebirds stay around during the winter,
they are unaccustomed to extremely cold weather during the month of November.As winter approaches, Bluebirds look for warm
places to roost during frigid nights.They often roost either inside the nest boxes they used during the past
summer or inside building structures where there are entrance ways into attics
or crevices that lead to the undersides of roof beams.These birds can also roost in pre-existing
cavities within large tree trunks, places where they have nested during warmer
weather.

However, when it came to finding warm winter roosting spots,
I don’t think our Bluebirds had much warning last fall with our sudden frigid
temperatures and snow storms.It is said
that one of the worst enemies of the Bluebird is “Jack” – Jack Frost, that is.With “Jack” descending on us so quickly
during late 2014, I think it caught the Bluebirds off guard, and some of them
may have perished that month.

Our past winter of 2014 to 2015 was extremely cold, but we did
not have the record-breaking amount of snowfall that the Northeastern
US received.Nevertheless,
Jack Frost may have played a role in diminishing our Bluebirds’ winter survival
rate.

An unusual event began taking place around here in mid
January 2015 – one that may well have had a negative impact on our local
Bluebirds’ survival.

In mid-January, a contractor hired by our local power
company began chopping down trees and branches that were threatening to fall on
power lines during high winds and heavy snowfall.The process was noisy and lasted for several
weeks.

If any of those trees contained old woodpecker holes in
which Bluebirds were roosting at night, the tree-cutting process could have
caused some of our Bluebirds to lose their warm, nocturnal sleeping stations, resulting
in the demise of those birds.

I did notice that, when the contractor first began cutting trees,
a Pileated Woodpecker began appearing at my suet feeders and continued to do so
for many weeks thereafter.I have
wondered if the tree-cutting resulted in the removal of dead tree trunks inside
which the Pileated Woodpecker had been finding beetle larvae.Pileated Woodpeckers are able to feed on that
type of larvae during the cold months.The answer is unclear, but it seemed that SOMETHING had brought that
Woodpecker out in the open at exactly that time.

Female Pileated Woodpecker, morning of Jan. 12, 2015

Since we had so few Bluebirds around this past March, I took
that as an imperative to put up a Bluebird nest box.I began talking to my very mechanical
next-door neighbor about it.Perhaps, if
we put up a nest box, a pair of Bluebirds would find it and raise some babies
in it, resulting in an increased Bluebird population in our neighborhood during
the spring of 2016.

By mid-April I had purchased a Bluebird nest
box. I had already purchased one last October at a craft show, but that one was too heavy to be mounted on a thin pole. The reason for mounting the box on a pole would be to help guard against predators.

My neighbor was studying the specs for mounting the nest box. We began planning the location of the box in accordance with permission from our landlord and the guidelines for mounting Bluebird boxes.

Tree Swallow on wire

On April 17th, my neighbor and I were standing on our porch, discussing plans for the nest box. I pointed to a Tree Swallow that was perching on the nearby wire and told my neighbor, “That’s what we’ll probably get: Tree Swallows.” I said this because it was well past the beginning of the first brooding season for Bluebirds. Bluebirds can build two or three nests per season, but the first nesting season generally begins in March. By April 17th, our local Bluebirds were probably well underway with their first nests of the season.

We finally got the nest box mounted on April 24th.According to my research, we were far too
late to have Bluebirds claim the box for their first nest of the season.

Tree Swallows claim nest box, May 1, 2015

Just as I had suspected on April 17th, when I had pointed to the Tree
Swallow on the wire, we did not get Bluebirds claiming the box. On May
1st a pair of Tree Swallows showed up and began building a nest inside
the box that very day.

We were so fortunate to get birds claiming the nest box only
one week after we had mounted it!Although they were not Bluebirds, I was overjoyed!Tree Swallows eat flying insects, acting as a
natural form of pest control.And we
would be helping to increase our local population of this species, a species
that I had not begun to observe in this neighborhood until April 2013.

But on May 10th, the nest was hijacked!The poor Tree Swallows!The female was still in the process of
building a nest inside the box that morning, when, not just one, but TWO male
Bluebirds appeared and fought over the box.One Bluebird won, and then started fighting the male Tree Swallow for
possession of the box.

Sadly for the Tree Swallows, the Bluebird and his mate
won.They began adding to the nest,
building its edges up higher.

The magical part of the story is that yes, the Bluebird DID
hear me call its name on April 17th while I was talking to my
neighbor on the porch!Yes, we did get
Bluebirds!

Feeling sorry for the Tree Swallows who lost their nest, I convinced my neighbor to put up a second nest box, which he mounted on May 19th. The new nest box was mounted about 75 feet from the first one. It was the best location given the parameters for the mounting of Bluebird boxes and restrictions by my landlord regarding the location of the box.

Immediately, the two Bluebirds who had claimed the first
nest box began perching on the second box and investigating it.Oh no, I thought, will the Bluebirds prevent other
birds from using the second box?The
Bluebirds had seized their current box from the Tree Swallows; would they also
keep the second box under guard?

Below is a photo, taken May 20th, of the second nest box in the background, with the first nest box in the foreground. The Bluebirds who were nesting in the first nest box are perching on the fence near the second (more distant) box! The male Blue bird is on the top fence wire, and the female is on the second fence pole to the right of the second box. I do not know what type of bird is perching on top of the second box!

So, did any birds end up claiming the second nest box?And how about the Bluebirds?Did they continue to use the first box, or did they shift to the second box? And
did any eggs get laid in the first box?You can follow
this blog at the upper right to find out!

Thursday, May 21, 2015

The morning of May 10th began in typical fashion.The female Tree Swallow was perched on the
top of the nest box holding straw in her bill – straw to carry into the box to
finish building her nest.

While the female Tree Swallow flew into the nest hole with straw, the
male Tree Swallow would guard her from either the top of the box or from the nearby fence
post.

I wondered when the female would finish building the nest. She and her mate had claimed the nest box on May 1st, just one week after we had put it up, and she had started building the nest that very day.

The last time I had looked inside the box – on the evening of May 8th – there had been a beautifully woven, circular nest inside. Two dark feathers had been placed at the right front of the nest.

All seemed calm and peaceful that sunny morning of May 10th.But then, a surprising event occurred.A pair of Eastern Bluebirds showed up – male and
female – and landed on the box!The Tree Swallows were nowhere in sight.Perhaps they were flying over the nearby hayfield, catching a late
breakfast of flying insects.

Both the male and female Bluebirds immediately began investigating the box. While one bird perched on the top of the box, the other would peek through its entrance hole. The photo to the right shows the male on top of the box, with the female on the front. The hole does not show in the photo, but the female is pointing her bill toward it. From the photo you can see the brightness of the colors of the male in comparison to the duller colors of the female.

Eventually, the female Bluebird flew from the box, while the
male stayed.All at once, another male
Bluebird appeared, and a fight ensued between the two males – right on top of
the nest box!

I am not sure which Bluebird won the fight, but soon
afterward, the male Tree Swallow returned to the top of the box and started
another fight.This time, two different
species were fighting for ownership of the nest box – the Tree Swallow and the
newly arriving Bluebird!

As I watched the two males lunge at each other, one bird
dropped to the ground, and the other bird followed. For a few seconds, it looked like the Tree
Swallow was on top of the Bluebird, pecking away at him.

The Bluebird then escaped and flew to a nearby tree.I was hoping that he was not injured and that he
had survived the attack.

Later that day, I began second-guessing myself about having
seen two male Bluebirds fighting over the box earlier that morning.Perhaps one of the birds in the skirmish had
actually been the male Tree Swallow.In
the right type of sunlight, it might be easy to mistake a male Tree Swallow for
a male Bluebird because of the brilliant blue on their backs.

After all, our local Bluebirds are said to begin their first nests of the season around mid March at the earliest. It was now only May 10th and I had not yet seen any baby Bluebirds around here. Would our local male Bluebirds actually be searching for nest sites in early May?

In this region of the US, it is recommended to have Bluebird nest boxes up by mid March in order for the Bluebirds to use them for their first brood of the season. However, we were late mounting our nest box and did not get it up until April 24th. No chance of Bluebirds very soon, I thought! We were consoled with the thought that Bluebirds might use the box for their second brood, perhaps during late June after the Tree Swallows were finished with it.

I doubted whether our local Bluebirds, if they had begun
their early broods in March or April, would be finished with the stages of
egg-laying, egg-incubation, feeding and fledging the nestlings, and continuing
to feed the fledglings outside the nest for a couple of weeks thereafter.The period from the laying of the first egg
to the fledging of the young lasts at least 33, but sometimes up to 45, days. Another 12 days would have to be added to that because that is the length of time that baby Bluebirds still need to be fed once they leave the nest. And it is the male parent Bluebird who often endures the sole burden of feeding the fledglings because the female is sometimes off to build another nest during that time. Therefore, the length of time that a male is occupied with breeding activities can be from 45 to 57 days, at least a month and a half. And that does not include the time period of mating that precedes egg-laying.

Well, I suppose it would be possible for the male Bluebirds
to have completed their first brood of the season by May 10th.Or perhaps the males had experienced
unsuccessful nesting attempts or found their mates later in the season then
usual.Another possibility is that cold
weather had delayed early nesting attempts.

To attempt to solve the mystery, I reviewed my photos from May 10th
and found proof that I had indeed seen two male Bluebirds!Here is a photo I took of a tree in my yard
that morning.It shows two male Eastern
Bluebirds on the branches, identified by their bright blue plumage.(The females display a much duller blue and
have brownish heads.)In the photo, the
bird barely visible at the lower right next to the feeder is actually a Blue
Jay.

By the time the skirmishes were finished, it was late
morning.A pair of male and female
Bluebirds kept returning to the top of the box.I don’t know whether the male was the one who had been in the fight with
the Tree Swallow.But I do know that, by
the time the pair of Bluebirds seemed to have claimed the nest box, I didn’t see
either of the pair of Tree Swallows on or around it.

Meanwhile, the male and female Bluebirds continued to investigate
the box.Just as the Tree Swallows had
done nine days previously, the Bluebirds, one by one, would test the hole
for size and enter the box to examine its contents.Neither stayed in the box for
long.They were too busy checking out
the remainder of the box. The photo on the right shows the female peering inside the hole.

In the Eastern Bluebird species (and in other bird species
as well), the female is the one who must approve of the nest site.The male will first find the nest site and
“present” it to her, but she is the one who must give the go-ahead to use the
site for nesting.

The female Bluebird therefore seemed to be more thorough in
her investigation of the box.After all,
she was the one who would have to approve of it.Consequently, she diligently inspected the
outside of the box as well as the inside. The photo to the left shows the female examining the back of the box.

But wait! What about the Tree Swallows? They were the ones who had originally found the nest box on May 1st, only a week after we had mounted it. The female had started a nest that very day. She had begun gathering straw and grass in her bill and flying into the nest hole with it.

So which species would be using the nest – the Bluebirds or
the Tree Swallows?I began reading
stories of joint nests between the two species, nests in which both Bluebirds
and Tree Swallows would lay their eggs and help rear the young.

Time would tell whether Tree Swallows, Bluebirds, or both would be using the nest.You
can find out what eventually occurred by following this blog at the top right
of this page.

Sunday, May 17, 2015

This spring my next-door neighbor kindly put up a Bluebird nest box for me. After coordinating with our landlord about the location of the box and purchasing the box and the parts to mount it, we finally got it up on April 24th.

To our pleasant surprise, only one week later, on May 1st, a pair of birds landed on the box and began investigating it! The two birds took turns poking their heads in and out of the hole to make sure it was the right size. The photo on the right shows the male investigating the size of the hole.

One by one, the birds entered the nest box and peeked outside through the hole. One bird would perch on the roof of the box while the other investigated the inside of it.

The photo below shows the male on top of the box with the female inside the box peeking out:

When the birds were satisfied that the box would be suitable for their nest, the female began flying to the nest with straw and carrying it into the box. The male would guard the box from either its roof or a nearby fence post.

In the photo below, you can see the female on the left side with her feet clutching some straw, and the male guarding from the roof.

But the birds were not Bluebirds. Instead, they were Tree Swallows!

It was no surprise that Tree Swallows, rather than Bluebirds, decided to use the box. Although the box was designed for Bluebirds, we did not get it mounted until well after the beginning of the Bluebirds' nesting season, which begins in early to mid March.

However, I was just as delighted with the Tree Swallows as I would have been with Bluebirds. Tree Swallows are beautiful, too, and an adult Tree Swallow eats about 2,000 flying insects per day. And the best part was that we only had to have the box up for one week before the Tree Swallows discovered it!

Both male and female Tree Swallows have white breasts and bellies, with dark blue on their backs, wings, tails, and upper heads. The male is especially beautiful, especially when the sunlight hits his feathers exactly right, showing his lovely iridescent blue!

In the Tree Swallow species, it is the female who builds the nest. It
is the male who has the duty of guarding her and the nest box while she
is building it.

The female worked diligently, continuing to bring straw to the box
each day. The male would stand guard duty, either from the top of the
box or from the nearby fence post.

Sometimes the female would land on the roof of the box with straw in her beak to rest for a moment before taking it into the nest box. Sadly, it often took her several attempts to successfully carry the straw into the box.

Below you can see both the male and female on the roof of the box, the male displaying his brilliant, bright blue plumage and the female holding a few strands of straw in her bill.

I began to wonder what the inside of the box looked like. Was it a hodge-podge of straw and grass, or was it a neatly woven nest?

Around 6 p.m. on May 8th, my neighbor told me she had not seen the Tree Swallows guarding the box that afternoon. My curiosity then got the best of me, and I could no longer resist looking inside the box. About half an hour later, with the birds nowhere in sight, I ventured to the box, carefully opened the door, and looked inside.

What I saw was quite an amazement to behold! Strands of straw were woven into a cup shape, even with a couple of dark feathers in the front. You can see the strand of straw protruding on the left side of the nest, indicating that the nest was still a work in progress.

Just 30 minutes later, I sighted the female Tree Swallow on the wire above my driveway. She continued to perch there, softly twittering the whole time, and even let me take quite a few pictures of her.

All seemed peaceful, with everything going as it should. Little did I know that a surprise was to ensue just two days later. And that surprise was not to involve eggs or babies. Follow this blog to find out what the surprise was!